Surgical techniques for harvesting a vessel of a patient include inserting a dissection cannula, having a tapered transparent tip, through an incision near the vessel for visually tracking the vessel while dissecting connective tissue in the adventitial plane along the surface of the vessel. A balloon disposed immediately proximate the tapered tip may be inflated to dilate a perivascular cavity to about 3 centimeters diameter. Following formation of a perivascular cavity in this manner, the incision may be sealed and insufflating gas may be supplied to maintain the cavity in expanded or dilated condition. A different form of cannula including a dissection tool may be inserted through a gas-sealing port into the insufflated cavity to occlude and sever side-branch vessels using clip appliers and electrocautery shears to isolate or skeletonize the target vessel from the side-branch vessels.
In vessel-harvesting surgical procedures of this type, successive inflation and deflation of the balloon as the cannula is advanced along the vessel extends operative time and is subject to balloon ruptures that necessitate replacement during the surgical procedure. In addition, the endoscope used to visualize the vessel during side-branch ligation and transection may become covered with blood and tissue and fluids that blur the visual images of the vessel and side branches, and that necessitates time-consuming withdrawal of the cannula for cleaning of the tip and endoscopic lens. Also, the separate types of cannulas for formation of a perivascular cavity and for side-branch transection contributes to the costs of the procedure and to the clutter of instruments assembled in the operating arena.